I’ve a Maplin N96FY, a silver weather station with an external pole-mounted wind/rain/temperature combo that measures the weather.  This is logged to Weather Underground and via some NodeRED into a Twitter account.

I’ve long wanted to removed the internal LCD display which shows the barometric pressure and external weather, and just log directly from the radio mast but it has proved difficult to understand, and Jim Easterbrook’s excellent pywws program has connected and interpreted my data for a long time.  Now, I am getting USB lockups on my connection to the head display and wanted to see if I could read the data directly.

I’ve chosen a Jeelink at 433MHz (this is the frequency which my WH1081 reports on the nameplate at the back, some others transmit at 868MHz).  I believe that the 433MHz ISM band may go away in the future, but for now that is what I have got.  The next confusion is whether the Fine Offset device transmits in On-Off-Keying ‘OOK’ or uses FSK as apparently the devices have used a variety of these over the years.

I saw nRFmon, a little arduino sketch which does a good frequency spectrum analysis and tried it out – I can see lots of activity across the 433 band as shown below.  You may see some specks of activity in the narrow waterfall display (narrowed around 434 as that seemed the most ‘interesting’ area of the graph).

I now need to identify which may be my transmitter, and more importantly if it uses OOK or FSK protocol – at the moment I’m not sure how to determine which!